1. Field of the Invention
The present invention relates to intensified treatment of wastewater containing excreta that is contaminated with highly concentrated Nitrogen and dissolyed organic matter (COD). More particularly, plants such as algae and diatoms cultivated under a special environment are adopted to effectively remove the insoluble residues of Nitrogen and COD in nature.
2. Related Prior Art
There are three essential needs, i.e., water, air, and soil, for life to survive in this world. However, our environment is contaminated year by year to such a point that we have to worry about the drinking water and breathing air. Due to increasing pollutants, such as carbon dioxide (CO2), oxides of nitrogen (NOx) or dioxin in the air, the global weather becomes unstable. Furthermore, the toxic wastewater discharged from the industrial plants or farmland without sufficient treatment pollutes our reservoirs.
The facts listed below are a few of many life threatening water pollution issues stemming from livestock farms:    California officials identify agriculture, including cattle farms, as the major source of nitrate pollution in more than 100,000 square miles of polluted groundwater.    Huge open-air waste lagoons, often as big as several football fields, are prone to leaks and spills. In 1995 an eight-acre hog-waste lagoon in North Carolina burst its banks, spilling 25 million gallons of manure into the New River. The spill killed about 10 million fish and closed 364,000 acres of coastal wetlands to shell fishing.    From 1995 to 1998, 1,000 spills or pollution incidents occurred at livestock feedlots in 10 states and 200 manure-related fish kills resulted in the death of 13 million fish.    Ammonia, a toxic form of nitrogen released in gas form during waste disposal, can be carried more than 300 miles through the air before being dumped back onto the ground or into the water, where it causes algal blooms and fish kills.
These examples are only part of countless water pollution problems that current livestock farms face. Even with the current technology, the amount of COD and nitrogen generated are still large enough to cause pollution.
The tertiary treatment for the swine farm waste matters were evaluated in the laboratory and in full-scale micro-algal ponds and achieved the removal of COD, BOD, inorganic nitrogen and orthophosphate up to 57%, 69%, 79% and 74%, respectively. Despite much research, a complete treatment for swine excreta has not yet been developed. As a result, it still causes pollution in the water reservoirs.
Further research is ongoing to develop a bio-filter for lowering the highly concentrated nitrogen. Other research is being performed for developing a bio-film to lower COD concentrations. A study has reported that the removal rate of the COD is up to 65% (from 1500 to 380 mg/L) by using the bio-film.
Even though many studies are ongoing in the field of wastewater treatment, there are no perfect solutions developed to prevent water pollution.
Despite the tremendous efforts to reduce pollutants, the current technology is inadequate to effectively prevent the increasing pollution.